1. Field of the Invention
Aspects of the present invention relate to a light scanning unit reciprocatingly scanning a light in forward and reverse directions and an image forming apparatus having the same, and more particularly, to a light scanning unit and an image forming apparatus having the same easily distinguishing which of a forward direction or a reverse direction a scanning direction of a light beam is.
2. Description of the Related Art
In general, a light scanning unit is employed on an image forming apparatus (such as a printer, a digital copier, a facsimile, a multi-function peripheral, etc.), and other devices (such as a bar code reader). An image forming apparatus employing the light scanning unit forms a latent image on an image carrying body through a main scanning by a beam deflector, and a sub scanning by driving of the image carrying body.
The light scanning unit includes a light source to generate and emit a light beam having a predetermined wavelength, and a beam deflector to deflect the light beam emitted from the light source. The beam deflector can be a rotation type using a rotating body (such as a rotating multi surface mirror) and a hologram disk to deflect an inputted light beam in a direction, and a resonance mirror type using a resonance mirror reciprocatingly rotating in a predetermined angle to reciprocatingly scan an inputted light beam in forward and reverse directions.
Unlike the rotation type, in the beam deflector of the resonance mirror type, whether a scanning direction of the light beam is a forward direction or a reverse direction is to be correctly determined when an image signal is applied to the light source.
The light scanning unit employing the beam deflector of a conventional resonance mirror includes at least two light detecting units disposed in non-image forming sections respectively provided on opposite sides of an image forming section to determine whether the scanning direction is the forward direction or the reverse direction. In this case, the scanning direction may be determined through each light detecting unit, and an image signal corresponding to each scanning direction may be applied.
However, since the conventional light scanning unit includes at least two light detecting units, a manufacturing cost increases. Furthermore, since electric connection and disconnection and a signal processing with respect to each light detecting unit are necessary, a circuit configuration is complicated.